TW201700537A - Modified polycarbodiimide compound, curing agent, and thermosetting resin composition - Google Patents

Abstract

A modified polycarbodiimide compound according to the present invention is obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound with at least one aliphatic amine selected from the group consisting of diethylamine, methylisopropylamine, tert-butylethylamine, di-sec-butylamine, dicyclohexylamine, 2-methylpiperidine, and 2,6-dimethylpiperidine. A curing agent according to the present invention contains the modified polycarbodiimide compound. A thermosetting resin composition according to the present invention contains the curing agent, and a carboxyl group-containing resin having a carboxyl group in the molecules thereof or an epoxy resin having two or more epoxy groups per molecule thereof. As a result, it is possible to provide: a modified polycarbodiimide compound that makes it possible to cure a resin composition at a relatively low temperature and that suppresses the curing of a resin composition at a drying step prior to a thermosetting step for the resin composition; a curing agent containing the modified polycarbodiimide compound; and a thermosetting resin composition containing the curing agent.

Description

Modified polycarbodiimide compound, hardener and thermosetting resin composition

The present invention relates to a modified polycarbodiimide compound obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound, a hardener comprising the modified polycarbodiimide compound, and heat containing the hardener A curable resin composition.

A resin composition such as a photosensitive resin composition and a curable aqueous resin composition using a polycarbodiimide compound as a curing agent is known as a conventional technique (see, for example, Patent Documents 1 and 2). The polycarbodiimide compound is excellent as a curing agent for a resin composition in view of low toxicity. However, the polycarbodiimide has low solubility in various solvents, and since the reaction of the carbodiimide and the aggregation of the polymer are progressed and gelled in a solution state even in a cool place. Therefore, there are so-called problems of long-term preservation difficulties.

In order to solve such a problem, a modified polycarbodiimide compound is known as a conventional technique by modifying a polycarbodiimide derived from an aromatic diisocyanate compound with diisopropylamine. The stability is excellent (for example, refer to Patent Document 3).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2013-050549

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-297491

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2007-138080

The resin composition of the modified polycarbodiimide compound is used, and the resin composition is usually dried before thermal curing. In the drying step of the resin composition, in order to efficiently dry the resin composition, it is desirable to harden the resin composition as much as possible in the drying step. The drying temperature and the heat curing temperature of the resin composition may vary depending on the solvent used in the synthesis of the polycarbodiimide compound or the target resin to which the curing agent is added. Therefore, in addition to diisopropylamine, it is necessary to prepare a modified polycarbodiimide compound which can be used as a hardener at various drying temperatures and heat hardening temperatures. Further, when the modified polycarbodiimide compound is cured, it is desirable to reduce the yellowing of the cured main component and the substrate due to heating, and to suppress the yellowing of the cured resin. The thermosetting temperature at the time of hardening of the imine compound is low.

Accordingly, the present invention provides a modified polycarbodiimide compound, a hardener comprising the modified polycarbodiimide compound, and a thermosetting resin composition comprising the hardener, with the exception of In addition to diisopropylamine, an item of a modified polycarbodiimide compound which can be used at various drying temperatures and heat hardening temperatures is added as an object; wherein the modified polycarbodiimide compound can be hardened at a relatively low temperature. And inhibiting the resin composition before the heat hardening step The hardening of the resin composition in the drying step.

In order to achieve the above object, the inventors have found that the polycarbodiimide compound derived from a diisocyanate compound can be modified at a relatively low temperature by modifying a polycarbodiimide compound derived from a diisocyanate compound with a predetermined aliphatic amine. Further, the modified polycarbodiimide compound of the resin composition in the drying step before the thermosetting step can be inhibited, and the modified polycarbodiimide compound other than diisopropylamine can be added. And complete the present invention.

That is, the present invention is as follows.

[1] A modified polycarbodiimide compound selected from the group consisting of diethylamine, methylisopropylamine, tert-butylethylamine, di-secondary butylamine, dicyclohexylamine, 2-methyl An aliphatic amine of at least one selected from the group consisting of a piperidine and a 2,6-dimethylpiperidine is obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound.

[2] The modified polycarbodiimide compound according to the above [1], wherein the aliphatic amine is selected from the group consisting of diethylamine, tert-butylethylamine, di-secondary butylamine, and dicyclohexylamine. An aliphatic amine of at least one of the group consisting of 2-methylpiperidine and 2,6-dimethylpiperidine.

[3] The modified polycarbodiimide compound according to [2] above, wherein the aliphatic amine is selected from the group consisting of diethylamine, tert-butylethylamine, di- ortho-butylamine, and dicyclohexylamine. And at least one aliphatic amine in the group of 2-methylpiperidine.

[4] The modified polycarbodiimide compound according to [3] above, wherein the aliphatic amine is a di-secondary butylamine.

[5] The modified polycarbodiimide compound according to any one of [1] to [4] wherein the diisocyanate compound is an aromatic diisocyanate compound.

[6] The modified polycarbodiimide compound according to the above [5], wherein the aromatic diisocyanate compound is selected from the group consisting of 4,4'-diphenylmethane diisocyanate, An aromatic diisocyanate compound of at least one of the group consisting of 2,4-tolylene diisocyanate and 2,6-toluene diisocyanate.

[7] A hardening agent comprising the modified polycarbodiimide compound according to any one of [1] to [6] above.

[8] A thermosetting resin composition comprising a carboxyl group-containing resin having a carboxyl group in a molecule or an epoxy resin having two or more epoxy groups in one molecule, and hardening as described in the above [7] Agent.

[9] The thermosetting resin composition according to the above [8], wherein the resin containing a carboxyl group is selected from the group consisting of polyurethane resins, polyamide resins, acrylic resins, vinyl acetate resins, and polyolefin resins. And at least one resin of the group of polyimine resins.

According to the present invention, it is possible to provide a modified polycarbodiimide compound which hardens a resin composition at a relatively low temperature and which can suppress hardening of the resin composition in a drying step before the thermosetting step of the resin composition, and comprises the same The hardening agent of the modified polycarbodiimide compound and the thermosetting resin composition containing the hardening agent can simultaneously increase the content of the modified polycarbodiimide compound other than diisopropylamine.

[Formation of the Invention]

[Modified polycarbodiimide compound]

The modified polycarbodiimide compound of the present invention can be obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound with an aliphatic amine.

(aliphatic amine)

Since the polycarbodiimide compound derived from the diisocyanate compound can be modified, the decomposability of the self-polycarbodiimide compound is high, and the aliphatic amine used in the modified polycarbodiimide compound of the present invention is selected from In the group comprising diethylamine, methylisopropylamine, tert-butylethylamine, di-secondary butylamine, dicyclohexylamine, 2-methylpiperidine and 2,6-dimethylpiperidine At least one aliphatic amine; preferably selected from the group consisting of diethylamine, tert-butylethylamine, di-secondary butylamine, dicyclohexylamine, 2-methylpiperidine, and 2,6-dimethyl At least one aliphatic amine in the group of propylpiperidine; more preferably selected from the group consisting of diethylamine, tert-butylethylamine, di-secondary butylamine, dicyclohexylamine, and 2-methylperazine At least one aliphatic amine in the group of pyridine; further preferably di- or two-butylamine. Thereby, the drying temperature of the resin composition is set to a temperature lower than the temperature at which decomposition of the modified polycarbodiimide compound from the aliphatic amine begins, and the heat hardening temperature of the resin composition is set to be more aliphatic. The amine-modified polycarbodiimide compound starts to decompose at a higher temperature, whereby the hardening of the resin composition in the drying step can be suppressed, and the resin composition can be surely hardened in the thermosetting step. Further, the heat hardening temperature of the resin composition can be made relatively low. Furthermore, it can be increased A product of a modified polycarbodiimide compound other than diisopropylamine.

Further, the carbodiimide-modified group formed by modifying the carbodiimide group with an aliphatic amine hardly hardens the resin composition because of low reactivity. However, if the aliphatic amine decomposes from the modified polycarbodiimide compound, the carbodiimide-modified group will change back to the carbodiimide group before the aliphatic amine modification. As described above, since the reactivity of the carbodiimide group is high, if the aliphatic amine is decomposed from the modified polycarbodiimide compound, the resin composition becomes hot by the formed carbodiimide group. hardening. Further, when the self-modifying polycarbodiimide compound of the aliphatic amine has high decomposability, the amount of the carbodiimide group which is changed from the carbodiimide-modified group increases, so that the resin composition hardens. Effectively, the resin composition hardens more completely.

For example, in the case where the aliphatic amine is a di- or secondary butylamine, if the polycarbodiimide compound derived from the diisocyanate compound having the carbodiimide group of the formula (1) is modified with an aliphatic amine, the formation formula (2) A carbodiimide modified group. The carbodiimide-modified group of the formula (2) has low reactivity due to the steric hindrance of the moiety of the formula (3) in the formula (2). Then, when the di- or secondary butylamine is decomposed, a highly reactive carbodiimide group of the formula (1) is formed, and the modified polycarbodiimide compound can harden the resin composition.

-N=C=N- (1)

(polycarbodiimide compound)

The polycarbodiimide compound used in the modified polycarbodiimide compound of the present invention is a polycarbodiimide compound derived from a diisocyanate compound, preferably a polycarbodiimide compound derived from an aromatic diisocyanate compound. . Here, the diisocyanate compound means an isocyanate compound having two isocyanate groups in the molecule, and the so-called aromatic diisocyanate compound means an isocyanate compound in which two isocyanate groups present in the molecule are directly bonded to an aromatic ring. . The polycarbodiimide compound derived from the diisocyanate compound is, for example, a polycarbodiimide compound derived from an aromatic diisocyanate compound and a polycarbodiimide compound derived from an aliphatic diisocyanate compound. The polycarbodiimide compound derived from an aromatic diisocyanate compound is preferably a polycarbodiimide derived from an aromatic diisocyanate compound because it is excellent in heat resistance as compared with a polycarbodiimide compound derived from an aliphatic diisocyanate compound. Amine compound.

The polycarbodiimide compound derived from the diisocyanate compound has, for example, a group represented by the following formula (4).

(In the formula, R represents a residue from which an isocyanate group is removed from a diisocyanate compound.)

The aromatic diisocyanate compound which is a source of the polycarbodiimide compound used in the modified polycarbodiimide compound of the present invention may, for example, be 4,4'-diphenylmethane diisocyanate or 4,4'-diphenyl. Ether diisocyanate, p-phenylene diisocyanate, isophthalic diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, o-tolidine diisocyanate, naphthalene diisocyanate , 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4 '-Diphenyl ether diisocyanate. These may be used alone or in combination of two or more. From the viewpoint of heat resistance, a preferred aromatic diisocyanate compound is selected from the group consisting of 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, and 2,6-toluene diisocyanate. At least one of them.

(polycarbodiimide copolymer)

Further, the polycarbodiimide used in the present invention may be an aromatic polycarbodiimide copolymer having at least two or more carbodiimide groups in the molecule, which is at least one aromatic group. The diisocyanate compound is synthesized as a raw material.

As the above copolymer, an aromatic polycarbodiimide can be used, for example, a polyether polyol, a polyester polyol, a polycarbonate polyol, or the like. Polybutadiene diol or the like obtained by copolymerization.

(Method for producing polycarbodiimide compound)

The polycarbodiimide compound used in the modified polycarbodiimide compound of the present invention can be produced by various methods using a diisocyanate compound as a raw material. For example, a method of producing an isocyanate terminal polycarbodiimide by a decarbonation condensation reaction with decarbonation of an aromatic diisocyanate compound (U.S. Patent No. 2941956, Japanese Patent Publication No. Sho 47-33279, J. Org. Chem, 28, 2069-2075 (1963), Chemical Review 1981, Vol. 81, No. 4, p619-621, etc.).

The decarbonation condensation reaction of the above aromatic diisocyanate compound is carried out in the presence of a carbodiimidation catalyst. Examples of the carbodiimidation catalyst include 1-phenyl-2-phospholene-1-oxide (1-phenyl-2-phospholene-1-oxide) and 3-methyl-1- Phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxidation And a phospholene oxide such as a 3-phospholene isomer such as these, and among them, 3-methyl-1-phenyl-2 is particularly preferable from the viewpoint of reactivity. -phospholene-1-oxide. The amount of the carbodiimide catalyst is usually 0.1 to 1.0% by mass based on the aromatic diisocyanate compound used for the carbodiimidation.

The decarbonation condensation reaction of the aromatic diisocyanate compound can be carried out without a solvent or in a solvent. Examples of the solvent that can be used include tetrahydroxyfuran (THF, tetrahydroxyfuran) and 1,3-two. An alicyclic ether such as an alkane or a dioxolane; an aromatic carbonized water such as benzene, toluene, xylene or ethylbenzene; chlorobenzene, dichlorobenzene, trichlorobenzene or tetrachloroethylene (Perclene) a halogenated hydrocarbon such as trichloroethane or dichloroethane; an ester solvent such as ethyl acetate or butyl acetate; and methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, etc. Ketone solvent. These may be used alone or in combination of two or more. Among these, toluene, tetrahydroxyfuran and methyl ethyl ketone are preferred.

The temperature of the above decarbonation condensation reaction is not particularly limited, but is preferably 40 to 200 ° C, more preferably 50 to 130 ° C. In the case of carrying out the reaction in a solvent, it is preferably from 40 ° C to the boiling point of the solvent. Further, in the case where the reaction is carried out in a solvent, the concentration of the aromatic diisocyanate compound is preferably from 5 to 55% by mass, more preferably from 5 to 40% by mass. When the concentration of the aromatic diisocyanate compound is 5% by mass or more, the synthesis of the polycarbodiimide does not take much time, and when it is 55% by mass or less, gelation during the reaction can be suppressed. Further, the solid content concentration at the time of the reaction is preferably from 5 to 55% by mass, more preferably from 20 to 50% by mass, based on the total amount of the reaction system.

(end of aromatic polycarbodiimide)

Further, in the present invention, a polycarbodiimide which uses a compound which reacts with a terminal isocyanate group of a polycarbodiimide such as a monoisocyanate to control the molecular weight to an appropriate degree of polymerization can be used. By.

As such a monoisocyanate for sealing the end of the polycarbodiimide for controlling the degree of polymerization, for example, phenyl isocyanate, p-tolyl isocyanate, m-tolyl isocyanate, p-isopropylphenyl isocyanate can be used. Wait. In particular, it is suitable to use phenyl isocyanate.

In addition, as a terminal blocking agent, it can be reversed with the terminal isocyanate. The compound can be used: methanol having a hydroxyl group, isopropanol, phenol, polyethylene glycol monomethyl ether, etc.; butylamine having an amine group, diethylamine, etc.; propionic acid having a carboxyl group, benzoic acid, etc. A compound such as an acid anhydride.

(Modification of polycarbodiimide compound using aliphatic amine)

As described above, the modified polycarbodiimide compound of the present invention is obtained by modifying a polycarbodiimide compound with an aliphatic amine. The modification of the polycarbodiimide compound using an aliphatic amine can be carried out, for example, in the following manner. The modification of the polycarbodiimide compound using an aliphatic amine can be carried out without a solvent, but can also be carried out by mixing the above polycarbodiimide compound with an organic solvent with respect to the carbodiimide group. An aliphatic amine is added thereto in a predetermined equivalent amount, and the mixture is stirred and reacted to carry out synthesis.

The amount of the aliphatic amine to be added in the case of using an organic solvent is preferably from 1 to 2 equivalents per 1 equivalent of the carbodiimide group, and the amount of excess aliphatic amine is small, and the amine is easily escaped from the so-called heat treatment. In terms of scattered points, it is preferably 1 to 1.2 equivalents. Further, the reaction temperature of the modification of the polycarbodiimide compound using an aliphatic amine is preferably room temperature (about 25 ° C) or 40 to 80 ° C from the viewpoint of the reaction rate and the side reaction for suppressing the modification. . The modification of the polycarbodiimide compound using an aliphatic amine is preferably carried out while stirring, and the reaction time varies depending on the temperature, but is preferably about 0.1 to 10 hours.

(hardener)

The hardener of the present invention comprises the modified polycarbodiimide compound of the present invention. Thereby, if the hardener of the present invention is used, the resin is composed The drying temperature of the material is set to be lower than the decomposition starting temperature of the modified polycarbodiimide compound from the aliphatic amine, and the thermosetting temperature of the resin composition is set to be modified from the aliphatic amine. The decomposition of the imine compound starts at a higher temperature, and the resin composition in the thermosetting step is surely hardened while suppressing the hardening of the resin composition in the drying step. Further, the heat curing temperature at the time of curing the resin composition can be made relatively low. Further, a preferred heat curing temperature is 90 to 150 °C. When the heat curing temperature is 90 to 150 ° C, the thermosetting resin composition can be sufficiently cured, and deterioration due to heating of the main agent or the substrate and yellowing of the cured resin can be suppressed.

[thermosetting resin composition]

The thermosetting resin composition of the present invention comprises the curing agent and resin of the present invention. The resin contained in the thermosetting resin composition of the present invention is not particularly limited as long as it is a resin which is crosslinked with a carbodiimide group, and for example, a resin having a carboxyl group in a molecule or having a carboxyl group in one molecule Two or more epoxy resins such as epoxy groups. From the viewpoint of easiness of the crosslinking reaction with the carbodiimide group, a preferred carboxyl group-containing resin is selected from the group consisting of a polyurethane resin, a polyamide resin, an acrylic resin, a vinyl acetate resin, and a polyolefin. A resin of at least one of a group of a resin and a polyimide resin.

The thermosetting resin composition of the present invention preferably contains, for example, 0.5 to 1.5 equivalents of the curing agent of the present invention, more preferably 0.8 to 1.2 equivalents, based on the functional group equivalent of the main component (resin). Moreover, the thermosetting resin composition of the present invention can be appropriately blended with various additives such as a pigment, a filler, and a leveling agent, depending on the application and the like. , surfactant, dispersant, plasticizer, UV absorber, anti-oxidation Chemical agent, etc.

By coating the thermosetting resin composition of the present invention on a predetermined substrate, a coating layer can be formed to obtain a coating film. In this case, a conventionally known method can be suitably used as the coating method, and for example, brush coating, Tampon coating, spray coating, thermal spraying, airless spraying, roll coating, curtain flow coating can be used. ), flow coating, dip coating, knife edge coating, and the like. After the formation of the coating layer, heat treatment can be performed in order to promote the crosslinking reaction. The heat treatment method is not particularly limited, and methods such as an electric heating furnace, an infrared heating furnace, and a high-frequency combustible furnace can be employed.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited thereto. In addition, "%" in the following text is based on quality unless otherwise stated.

[Production of modified polycarbodiimide compound]

The modified polycarbodiimide compound of the examples and the comparative examples was produced by using the polycarbodiimide compound produced in any of the following Synthesis Examples 1 to 3 as follows.

(Synthesis Example 1)

100 parts by mass of toluene diisocyanate (composition: 80% of 2,4-toluene diisocyanate, 20% of 2,6-toluene diisocyanate), and 71.8 parts by mass of polyalkylene carbonate diol (Asahi Kasei Chemicals ( )), DURANOL T-5651, molecular weight 1000), 17.1 parts by mass of phenyl isocyanate, 245 parts by mass of toluene (boiling point 110.6 ° C) and 1.0 part by mass of carbodiimide catalyst (3-methyl-1) -Phenyl-2-phospholene-1-oxide) was placed in a reaction vessel equipped with a reflux tube and a stirrer, and stirred at 100 ° C for 3 hours under a nitrogen stream, and confirmed by infrared absorption (IR) spectroscopy. The absorption peak derived from the isocyanate group before and after the wavelength of 2270 cm ^{-1 was} substantially disappeared, and the absorption peak derived from the carbodiimide group before and after the wavelength of 2150 cm ^{-1 was} confirmed to obtain the polycarbodiimide compound of Synthesis Example 1.

(Synthesis Example 2)

100 parts by mass of toluene diisocyanate (composition: 80% of 2,4-toluene diisocyanate, 20% of 2,6-toluene diisocyanate), and 71.8 parts by mass of polyalkylene carbonate diol (Asahi Kasei Chemicals ( )), DURANOL T-5651, molecular weight 1000), 17.1 parts by mass of phenyl isocyanate, 245 parts by mass of tetrahydrofuran (THF, boiling point 66 ° C) and 1.0 part by mass of carbodiimide catalyst (3-methyl -1-Phenyl-2-phospholene-1-oxide) was placed in a reaction vessel equipped with a reflux tube and a stirrer, and stirred under a nitrogen stream for 6 hours under reflux with a solvent by infrared absorption (IR). In the spectrum measurement, it was confirmed that the absorption peak derived from the isocyanate group before and after the wavelength of 2270 cm ^{-1 was} substantially disappeared, and the absorption peak derived from the carbodiimide group before and after the wavelength of 2150 cm ^{-1 was} confirmed, and the polycarbodiimide compound of Synthesis Example 2 was obtained. .

(Synthesis Example 3)

100 parts by mass of toluene diisocyanate (composition: 80% of 2,4-toluene diisocyanate, 20% of 2,6-toluene diisocyanate), and 71.8 parts by mass of polyalkylene carbonate diol (Asahi Kasei Chemicals ( )), DURANOL T-5651, molecular weight 1000), 17.1 parts by mass of phenyl isocyanate, 245 parts by mass of methyl ethyl ketone (MEK, boiling point 79.5 ° C) and 1.0 part by mass of carbodiimide catalyst ( 3-methyl-1-phenyl-2-phospholene-1-oxide) was placed in a reaction vessel equipped with a reflux tube and a stirrer, and stirred under a nitrogen stream for 5 hours under reflux with a solvent, by infrared In the absorption (IR) spectrum measurement, it was confirmed that the absorption peak derived from the isocyanate group before and after the wavelength of 2270 cm ^{-1 was} substantially disappeared, and the absorption peak derived from the carbodiimide group before and after the wavelength of 2150 cm ^{-1 was} confirmed, and the carbonization of Synthesis Example 3 was obtained. Diimine compound.

(Example 1)

The polycarbodiimide compound obtained in Synthesis Example 1 was further placed in a reaction vessel, and the polycarbodiimide compound was cooled to 50 ° C, and 42.8 parts by mass of diethylamine (DEA) was added thereto, followed by stirring for 5 hours. Then, it was confirmed by infrared absorption (IR) spectroscopy that an absorption peak derived from a thiol group was generated before and after a wavelength of 1660 cm ^-1 , and an absorption peak derived from a carbodiimide group before and after a wavelength of 2150 cm ^-1 substantially disappeared, and was obtained. The modified polycarbodiimide compound of Example 1.

(Examples 2 to 7, Comparative Examples 1, 2, and Reference Example 1)

The examples 2 to 7 were obtained in the same manner as in the modified polycarbodiimide compound of Example 1, except that the carbodiimide compound to be used, the aliphatic amine to be added, and the amount thereof to be added are shown in Table 1. And Comparative Examples 1 and 2, the polycarbodiimide compound of Reference Example 1.

[Evaluation of modified polycarbodiimide compounds]

(decomposition of aliphatic amines)

The modified polycarbodiimide compounds of Examples 1 to 7, Comparative Examples 1, 2 and Reference Example 1 were heated at 170 ° C, and the modified polycarbodiimide compound after heating for 30 minutes was measured for infrared absorption. (IR) spectrum. Then, the peak intensity of the absorption peak of the carbodiimide group in the vicinity of the wavelength of 2150 cm ^{-1 of the} measured infrared spectrum was detected. The intensity of the peak of the absorption peak of the carbodiimide group in the polycarbodiimide compound before the modification with the aliphatic amine is determined by the intensity of the peak detected, and the carbonized secondary product formed by the decomposition of the heated aliphatic amine is calculated. The ratio (%) of the peak intensity of the amine group was used to calculate the decomposability of the aliphatic amine in the modified polycarbodiimide compound. In the case where the decomposability value is 100%, it is presumed that the carbodiimide-modified group is all converted into a carbodiimide group by decomposition of an aliphatic amine. In addition, infrared absorption (IR) spectroscopy was performed using FT-IR8200PC (manufactured by Shimadzu Corporation).

(Decomposition starting temperature of aliphatic amine)

The modified polycarbodiimide compounds of Examples 1 to 7, Comparative Examples 1, 2 and Reference Example 1 were heated at 50 to 160 ° C for 15 minutes to determine the heated modified polycarbodiimide compound. Infrared absorption (IR) spectroscopy. Then, the presence or absence of the absorption peak of the carbodiimide group in the vicinity of the wavelength of 2150 cm ^{-1 of the} measured infrared spectrum was examined. In the case where there is no absorption peak of the carbodiimide group, it is judged that the aliphatic amine is not decomposed in terms of the heating temperature; in the case of the absorption peak of the carbodiimide group, it is judged that the heating temperature is aliphatic. Amine decomposition. Then, the lowest temperature at which the heating temperature at which the aliphatic amine is decomposed is determined as the decomposition starting temperature.

(hardening test)

The modified polycarbodiimide compound (NCN equivalent: 134) of Examples 1 to 7, Comparative Examples 1 and 2 and Reference Example 1 was mixed with a carboxyl group-containing polyurethane resin (COOH equivalent: 1100). This was made into NCN equivalent: COOH equivalent = 1:1, and the thermosetting resin composition was prepared. Next, the thermosetting resin composition flow was extended to the release PET film, and dried at the drying temperature shown in Table 1 for 5 minutes, and then heated at 80 to 160 ° C for 1 hour. A film having a thickness of about 20 μm was produced. Next, whether or not the film was cured was examined using a dynamic viscoelasticity measuring device (DMA) (manufactured by SII NanoTechnology, trade name: DMS6100). Here, when the glass transition temperature of the film measured by the dynamic viscoelasticity measuring apparatus (DMA) was 80 ° C or more, it was judged that the film was hardened. Then, the lowest temperature among the heating temperatures at which the thermosetting resin composition is cured is set to the curing temperature.

[Evaluation results]

The evaluation results of the modified polycarbodiimide compounds of Examples 1 to 7, Comparative Examples 1 and 2 and Reference Example 1 are shown in Table 1.

According to the evaluation of the decomposability of the above aliphatic amine and the evaluation of the decomposition starting temperature of the aliphatic amine, it can be known that the modified polycarbodiimide compound of Examples 1 to 7 is used as a curing agent, that is, by using Using a group selected from the group consisting of diethylamine, methylisopropylamine, tert-butylethylamine, di-second-butylamine, dicyclohexylamine, 2-methylpiperidine, and 2,6-dimethylpiperidine The at least one aliphatic amine in the group is a modified polycarbodiimide compound obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound as a hardener, and the resin composition can be hardened at a relatively low temperature. And the hardening of the resin composition in the drying step before the thermosetting step of the resin composition can be suppressed. On the other hand, it can be known that if the modified polycarbodiimide compound of Comparative Examples 1 and 2 is used as a hardener, that is, if the polyisocyanate compound is carbonized by using di-n-butylamine and diisobutylamine, The modified polycarbodiimide compound obtained by modifying the imine compound as a curing agent has a need to increase the thermosetting temperature. I think this is because di-n-butylamine and diisobutylamine have low decomposition and high decomposition start temperature. Further, since the decomposability of the modified polycarbodiimide compound of Examples 1 to 7 is the same as that of the diisopropylamine of Reference Example 1, it is understood that the modified polycarbodiimide compounds of Examples 1 to 7 can be used. Used as a product other than diisopropylamine.

[Industrial availability]

The modified polycarbodiimide composition of the present invention has high adhesion strength and high heat resistance because of its solution storage stability, and is suitable for use as various electronic parts, such as a base film and a cover film for a wiring board. Or a raw material such as a film. In particular, the modified polycarbodiimide copolymer has further flexibility and resistance to bending ( The bending resistance is also excellent, so it is particularly suitable for use as a base film or a cover film for a flexible wiring board. Moreover, the modified polycarbodiimide compound of the present invention and the curing agent of the present invention can be used as a curing agent for a resin composition such as a photosensitive resin composition and a curable aqueous resin composition.

Claims (9)

A modified polycarbodiimide compound selected from the group consisting of diethylamine, methylisopropylamine, tert-butylethylamine, di- or di-butylamine, dicyclohexylamine, 2-methylpiperidine And at least one aliphatic amine in the group of 2,6-dimethylpiperidine is obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound. The modified polycarbodiimide compound according to claim 1, wherein the aliphatic amine is selected from the group consisting of diethylamine, tert-butylethylamine, di- ortho-butylamine, dicyclohexylamine, 2-methyl An aliphatic amine of at least one of the group consisting of piperidine and 2,6-dimethylpiperidine. The modified polycarbodiimide compound according to claim 2, wherein the aliphatic amine is selected from the group consisting of diethylamine, tert-butylethylamine, di- ortho-butylamine, dicyclohexylamine, and 2-methyl At least one aliphatic amine in the group of piperidines. The modified polycarbodiimide compound according to claim 3, wherein the aliphatic amine is di-secondary butylamine. The modified polycarbodiimide compound according to claim 1, wherein the diisocyanate compound is an aromatic diisocyanate compound. The modified polycarbodiimide compound according to claim 5, wherein the aromatic diisocyanate compound is selected from the group consisting of 4,4'-diphenylmethane diisocyanate and 2,4-toluene. An aromatic diisocyanate compound of at least one of the group consisting of 2,4-tolylene diisocyanate and 2,6-toluene diisocyanate. A hardener comprising the modified polycarbodiimide compound according to any one of claims 1 to 6. A thermosetting resin composition comprising a carboxyl group-containing resin having a carboxyl group in a molecule or an epoxy resin having two or more epoxy groups in one molecule, and a curing agent according to claim 7. The thermosetting resin composition of claim 8, wherein the carboxyl group-containing resin is selected from the group consisting of a polyurethane resin, a polyamide resin, an acrylic resin, a vinyl acetate resin, a polyolefin resin, and a polyimine. At least one resin in the group of resins.